Preparation Of Thermosensitivity（PNIPAM-co-MAH-β-CD）/（MWCNTs-TiO₂） Composite Photocatalyst And Its Study On Photocatalytic Activity

As the main source of industrial wastewater, alkyl dinitrophenols wastewater was the first target of the wastewater treatment because of it’s high concentration, color depth, organic matter complex composition, strong toxicity and non-biodegradable. As a kind of semiconductor photocatalytic, TiO2attracted a great deal of attention owning to its non-toxic, low-cost, high reactivity and oxidability, thoroughly degrading, non-selective, less secondary pollution characteristics. Because of the charatceristics mentioned before, it is important to further the study of TiO2for the degredation of dinitrophenol wastewater in both theoretical and practical aspects. However, deficiencies of TiO2photocatalyst such as low efficiency in the solar, poor interfacial compatibility between TiO2and organic photocatalytic technology to further development and industrialization.Our previous researches showed that we can achieve a kind of TiO2photocatalyst which can response to the visible light through the combination of MWCNTs with TiO2. In this paper, based on the study of MWCNTs-TiO2photocatalysts, a novel (PNIPAM-co-MAH-β-CD)/(MWCNTs-TiO2) composite photocatalyst was successfully synthesized by introduction of temperature sensitive non-ionic unit of poly N-isopropyl acrylamide (PNIPAM) and organic envelope to identify unit of maleic anhydride (MAH)modified β-cyclodextrin (MAH-β-CD). This composite photocatalyst overcome the dificiencies of typical TiO2and achieved characteristics such as response-to-visible-light, higher photocatalytic efficiency, better miscibility in organic compounds and cyclic utilization. This provides both theoretical and practical basis for the industrialization of the TiO2photocatalytic technology. Researches in this paper involve the following parts:(1)A novel (PNIPAM-co-MAH-β-CD)/(MWCNTs-TiO2) composite photocatalyst was successfully synthesized by copolymerization of PNIPAM, MAH-P-CD and MWCNTs-TiO2under UV light irradiation. The prepared composite photocatalysts were characterized by FT-IR、UV/DRS、EA、13C-NMR、XRD、SEM、TEM and TG-DTG. The change of swelling ratio under different temperatures reflected its thermosensitivity, which realized the recycle of photocatalyst.(2) The process of photolyzation was concerned towards the degradation of typical multi-nitrophenyl compound2-sec-butyl-4,6-dinitrophenol (DNBP) under visible light irradiation. Investigated the effects of catalyst preparation conditions such as initiate methord, monomer dosage ratio, initiate time, quantity of MWCNTs-TiO2and achieved the optimized technological conditions and parametres.(3) The prepared composite photocatalysts were evaluated for their photocatalytic activity towards the degradation of DNBP under visible light irradiation. The best degradation conditions of all the degradation factors, such as light, degradation time, pH of solution, catalyst concentration and DNBP concentration, were obtained in the degradation process. Studies have shown that composite photocatalyst synthesized was with visible light response, which effectively improved the quantum efficiency of the TiO2photo. Furthermore, the temperature sensitive nature of the catalyst hasfacilitated the recovery of the catalyst, which means the catalyst can be recycled.